Wednesday, March 4, 2020

VP Ratchet Climber Lock

Many teams have asked us about our climber break from last season. We mentioned possibly using it this season and showed a small CAD image.

We want to give a full story into the development of this break.

Last season we planned to use the VP ratchet in a normal way and have a cylinder pull a string to disengage the pawl.  When we did that we either could disengage the pawl or couldn't engage it properly. We also heard of people breaking the pawls.

While at champs we were looking for a way to brake our climber that didn't use the pawl. SOTAbots (FRC#25570 were in our division and they had a great climber break that they showed us. Here is a picture we took.

We worked in our pit to make a version of this but we couldn't custom make the parts they did. So we removed the out shell of the ratchet and just used the spacers. We also tried to use a normal bolt but we broke it, so instead, we just use the pneumatic rod end directly into the ratchet. We found that it didn't damage the rod end at all when doing this.

For IRI our setup looked like this.
IRI ratchet setup 2019.PNG
The VP dual input doesn't have the rear bolts so we need to clamp on the cylinder.

We have heard from several teams that have used this setup with great success. We aren't using it this year. For Dripping Springs we were able to just use our NEO climb motors in brake mode, with about a 30:1 reduction on our elevator and our robot would stay in the air for more than enough time to keep the climb.

We do have a latch mounted on our robot.
Climber Latch 2020.PNG
This latch uses a laser-cut Delrin ratchet that is pressed on to the pinion of one of our NEOs. We haven't tested this setup yet as we haven't needed it. We do plan to get it working so if we climb late enough to not be at the top of our climb we will stay off the ground.


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